Add exitcode and quiet mode

[breml]

Added two cli flags for:

• exitcode: provide an exitcode > 0 if the two input files do have differences
• quiet mode: suppress the output if there are no differences

[yudai]

Thanks for the PR.

I think the exit code should be non-zero by default when files are different. Could your remove the option and make it the default behavior?

[breml]

Updated the PR.

[yudai]

Thanks@